There is mounting evidence that microbial pathogens (particularly group A beta-hemolytic streptococci, GABHS) trigger acute episodes of Tourette's Syndrome (TS). Determining whether changes in the peripheral blood T lymphocyte population coincide with acute exacerbations of Tourette's Syndrome (TS) symptoms will be studied as well as identification of bacterial pathogens in the oropharynx or stool that initiate acute TS episodes. This is an ongoing study.